Safety device for power presses



Dec. l5, 1942.

. E. H. HALL. 2,305,472

SAFETY DEVICE FOR POWER PRESSES Filed Sept. 26, 1941 2 Sheets-She'et 1 l O 5 "2 gigi fz' ,I ze

O 0 i; 6] 60 .55 46 f5 UHU L f -I I 47 fkk Il "I .1.. f

Dec. 15, 1942. E, H, HALL l 2,305,472

SAFETY DEVICE FOR POWER PRESSES Filed Sept. 26, 1941 2 Sheets-Sheet 2 Patented Dec. 15, k1942 UNITED STATE s PATENT OFFICE Application September My invention relates to an attachment for intermittently operated machinery such as power presses and the like, the purpose being to provide a device which will assure that the operators hands are held away from a position ofl danger at the moment that the machinery is operated. To accomplish this end, flexible connections are extended from the operators arms to the machine to be pulled thereby with each operation thereof, a slight motion thus initiated being amplified to any extent that may be desired at the point where the operators arms are engaged. In this way it is possible to be sure that the operators arms will be drawn away from the work a suilicient distance for safety, even though the movement of the machine itself may be relatively small in extent. Y

Such an attachment as hereinafter described incorporates within itself a discerptible connection which may be broken promptly in the event of an emergency which requires that the operator befreed for a hurried departure from the machine. In the achievement of this end I extend the `llexible connections through an enclosed fixed path which lies close to, but slightly spaced from, a knife blade or the like with which certain discerptible end portions normally never engage. By a slight movement in an abnormal direction, however, these end portions are drawn across the knife blade so as to be Vreadily severed thereby, whereupon the operator is free to leave thermachine even though the connections may not have beenrdisengaged from his arms.

. A suggestive embodiment of this invention as applied to a power press is set forth in the accompanying drawings wherein;

Figure 1 is a side elevation of a press showing the attachment in operative position thereupon;

Fig. 2 is a horizontal section, taken on line 2-2 of Fig. 1;

Fig. 3 is a detail in vertical section, showing a block and tackle arrangement incorporated with one of the flexible connections; p

Fig. 4 is an enlarged detail inr section, taken on line 4-4 of Fig. 2; and X Fig. 5 is a view in perspective of the holderwith attached knife that is associated with each of the flexible connections.

The power press shown in Figs. 1 and 2 is conventional in that it comprises a bed I above which is a vertically reciprocable slide II operated as by a pitman I2 which is driven fromk an eccentric i3 on the shaft I4, the whole being supported upon the frame I which may be pivotally mountedras at I6 upon a base support I1.

cord 39.

The frame may be tilted to various adjusted positions inv each of which a bolt l8 carried thereby is adapted to be shifted within an arcuate slot IS and thereby clamped with the aid of a nut 20 in a selected position of adjustment.

The present attachment is adapted for use with various kinds of machinery of which they power pressl just described is one example. As shown,` the device .comprises a bell crank, pivoted to the machine as at 25, and formed with a horizontal arm a and a depending vertical arm b. Extending fromk the free end of the horizontal arm a and in connection therewith is a,

link 26 having an adjustable connection at 21 with `an armg that is extended rearwardly from the slide so as to be operated thereby. The bell crank is accordingly rocked with each operation of the slide. The free end of the depending vertical arm b of the bell crank lies opposite one end of an enclosure in the form of` an enclosed guideway in the form of a tube 3b which is supported upon the machineV with the aid of a holder 3l.

In connection with the -free end of the bell crank arm b is a link 35 extended froma block 36 mounting, one or more sheaves 3'I, the block also providing an eye 38 to which is secured fast one end of a flexible tackle, here indicated as a A This cord extends, lengthwise within the tubular guideway for passage over one or more sheaves Iii) carried in a second block- 4I, and then back for passage over one or more of the sheaves 3l so as to produce a desired amplification of movement ofthe cord at its remote end. A rod 45 having an adjustable connection with the block 4I extends away therefrom to present its remote end through a bearing 46 in the 'guideway 30, and on this end of the rod is a polygonal head 41 which is adapted to rest against the end of the bearing. By suitable ad- `j ustments of the rod, the position of the block 4I may be shifted toward and from the other block 36 so as to vary the distance therebetween. The block and tackle system just described may be single or duplex, but in either case two discerptible cords, both alike, leave the tubular guideway, one :l: through an elongated opening 5I adjacent a sheave 52 around which it passes, andthe other y through an elongated opening 53 adjacent another sheave 54 around which it passes.

As shown best in Fig. 2, the guideway extends away from the press and then, at 55, executes a bend of or so to continue on parallel with the front ofthe press, but at adistance therefrom which is to the rear of the operator. The sheave 52 is located substantially at the bend so that the cord :c which passes therearound and out through the opening l is located conveniently to the right hand side of the operator who is stationed before the machine. The other sheave 54 is located near the remote end of the guideway so that the cord y passing therearound comes out at the left hand side of the operator. Each cord connects at its end with an armlet 56 through which the operators arms are extended at all times while remaining on duty before the machine.

A feature of importance in this invention is the use of a severing device adjacent each cord at the point where it emerges from` the tubular guideway. As shown, this device comprises in each case a split collar 50: adapted to be fitted around the guideway with a bolt El extended through a pair of ears outturned therefrom. Each collar occupies a position lengthwise of the guideway which is over one slotted opening 5I for al portion of its length, and is formed at a point desirably opposite its split with an obliquely disposed flat base 55 Whereon may be mounted a blade 55 whose knife edge 61 is presented outwardly and angularly toward the cord passing off of the proximate sheave 52 or 54, as the case may be. The knife blade is similarly supported with the aid of a stud bolt 6B which passes through the blade and into the collar base for screwthreaded connection therewith'. By such a construction, each blade is maintained near one end of the associated elongated opening 5l (or 53) and angularly in a direction which points toward the associated sheave 52 (or 54). In the event of a sudden emergency the operator may shift his position sufliciently to wipe each cord against the knife edge of the proximate blade, whereby to discerp the two cords and release the operator for a hurried departure from his confined position adjacent the machine.

The features of special advantage which characterize my invention resides largely in the simple yet effective block and tackle system. by which flexible and severable restraining cords are given a movement which may be amplified, as desired, with respect to the source of movement, Viz., the slide. Each cord is entirely enclosed within the same tubular guideway so as to be protected from extraneous contact except near its end where discerption is contemplated. In addition I have provided, in connection with each cord, a means by which to effect its quick breakage. The devices used for this purpose are located conveniently so as to be engaged when the occasion arises, but are normally so placed as not to be contacted by the operator, or by the cords of the safety attachment when in everyday use. The provision for discerption thus afforded is in itself a factor of safety of the utmost importance inl the event of an emergency requiring the operator to vacate suddenly his position before the machine.

This invention presents two aspects which may be conjointly used with advantage, viz., the protected connections by which movement is transmitted and amplified from the intermittently operating machine to the operators arms, and the discerptible end portions of such connections, adjacent the operators arms, so as to be co-operable with devices which will readily produce discerption in response to the special requisite motion therefor. The combining of these two features issimplified and improved by the use of a protecting guideway, here shown as a tube, through which the block and tackle mechanism is extended. Such a guideway may furnish a sliding support for the movable block and for the tackle which is actuated in response thereto. It also confines the tackle to fixed paths through which it is required to move, and provides an enclosure therefor except beyond the points where the sheaves are mounted to permit the connectionsy tov pass thereover enroute to the operators-arms. This same guideway mounts the sheaves in xed positions so as to determine at those points the path of movement of the flexible connections, and also supports adjacent each sheave the means which is relied upon to break such connections, i. e., the severing knife blades which occupy positions closely adjacent each sheave so as to furnish, in effect, a guard therefor.

I claim:

1. For use with an intermittently operating machine, a safety device comprising a block and tackle mechanism, means connecting the machine With one block to transmit a pulling force thereto, an anchorage to which the second block is secured, and flexible meansV extending from the tackle adapted for attachment to both arms of an attendant before the machine, and acting with each operation of the machine to constrain the attendants arms to remain away therefrom, the movement of the machine being amplified through the block and tackle mechanism to increase the extent of movement of the flexible means, and means for securing the anchorage in a selected position of adjustment whereby to vary the distance between the two blocks;

2. For use with an intermittently operating machine, a safety device comprising a block and tackle mechanism, a guideway for supporting the block and tackle mechanism in a substantially horizontal plane, means connecting the machine with one block to transmit a pulling force thereto, the guideway being extended through a path along one side of and to the rear of an attendant before the machine, an anchorage connecting the second block to the guideway, means exteriorly of the guideway in connection With the anchorage for shifting the position of the second block relative to the first block, flexible means extending from the tackle adapted for attachment to both arms of the attendant and acting with each operation of the machine to constrain the attendants arms to remain away therefrom, the movement of the machine being amplified through the block and tackle mechanism to increase the extent of the movement of the flexible means, and a pair of sheaves mounted on the guideway, one to each side of the operator and both to the rear thereof, adjacent points of departure therefrom of the flexible means extending from the tackle.

3. For use with an intermittently operating machine, a. safety device comprising a block and tackle mechanism, a tubular guideway for the block and tackle mechanism extending in a substantially horizontal plane along one side of and to the rear of an attendant before the machine, means connecting the machine with one block to transmit a pulling force thereto, an anchorage to which the second block is secured, means in adjustable connection with the anchorage for shifting the position of the second block relative to the rst block, a pair of sheaves carried on the guideway each opposite an opening therethrough, one adjacent each side of the attendant and both to the rear thereof, and a pair of flexible means extending from the tackle, each passing out from the tubular guideway around one of the sheaves thereon, adapted for attachment to the arms of the attendant before the machine, and acting with each operation of the machine to constrain the attendants arms to remain away therefrom, the movement of the machine being amplified through the block and tackle connection to increase the extent of the movement of the flexible means.

4. For use with an intermittently operating machine, a safety device comprising a block and tackle mechanism, means connecting the machine With one block to transmit a pulling force thereto, an anchorage to which the second block is secured, flexible connections extending from the tackle and provided with discerptible free end portions having means for attachment to both arms adjacent the elbows of an attendant before the machine, and acting with each operation of the machine to constrain the attendants arms to remain away therefrom, means for guiding the exible connections through a xed path of movement up to points relatively close to the attendants arms, said guiding means having openingsarranged to permit abnormal movement of said free end portions along the guiding means,

`and a device iixedly mounted at said openings adjacent the discerptible free end portions of the flexible connections, inproximity to the guiding means, and engageable by the discerptible portions of the connections when the free ends thereof are swung around to an abnormal position adjacent thereto, operable to break the con- Y nections whereby to free the attendant.

5. For use with an intermittently operating machine, a safety device comprising connections extending from the machine and provided with discerptible flexible free end portions, havingy means for attachment to the arms adjacent the elbows of an attendant before the machine, and acting with each operation of the machine to constrain they attendants arms to remain away therefrom, means for guiding and supporting the flexible free end portions of the connections at a point relatively close to the attachingvends thereof, a device adjacent the flexible discerptible free end portions of the connections close to the guiding and supporting means, coacting with the said connections when the free end portions thereof are swung around to a position of engagement therewith, operable to break the free end portions whereby to free the attendant, and means for guiding said flexible end portions into engagement with said device.r

6. For use with an intermittently operating machine, a safety device comprising connections extending from the machine and provided with flexible discerptible free end portions, adapted for attachment to the arms adjacent the elbows of an attendant before the machine, and acting with each operation of the machine to constrain the attendants arms to remain away therefrom, guiding means for the flexible discerptible free end portions at points rearwardly of the operator, 'a device fixedly mounted adjacent the guiding means and coacting with the flexible discerptible free end portions when the latter are swung around to a, position of engagement therewith, operable` to break the free end portions whereby to free the attendant, said guiding means having openings through which said end portions pass arranged tov guide said end portions into engagement with said device.

' EDWARD H. HALL. 

